1. Field of the Invention
This invention relates to a magnetic recording medium for use in a magnetic recording apparatus using a magnetic tape, magnetic disk, or the like. This invention particularly relates to a thin metal film type magnetic recording medium exhibiting improved corrosion resistance and durability.
2. Description of the Prior Art
Many of the conventional magnetic recording media are of the so-called coating type and are made by using powdered magnetic materials such as magnetic oxide particles such as .gamma.-Fe.sub.2 O.sub.3, Co-doped .gamma.-Fe.sub.2 O.sub.3, Fe.sub.3 O.sub.4, Co-doped Fe.sub.3 O.sub.4, Berthollide compounds of .gamma.-Fe.sub.2 O.sub.3 and Fe.sub.3 O.sub.4, Co-doped Berthollide compounds, or CrO.sub.2, or magnetic alloy particles containing, as main constituents, Fe, Ni, Co and the like. These powdered magnetic materials are dispersed in organic binders such as vinyl chloride-vinyl acetate copolymers, styrene-butadiene copolymers, epoxy resins and polyurethane resins. The dispersions thus obtained are then applied to non-magnetic substrates and dried to form the magnetic recording media.
Recently, so-called thin metal film type magnetic recording media using no binders have attracted attention because of their ability to meet strong demand for high density recording. The magnetic recording media of this type have magnetic recording layers which consist of thin ferromagnetic metal films formed by a process such as vacuum deposition, sputtering, ion plating or plating. Thus various efforts are being made to develop thin metal film type magnetic recording media suitable for practical use.
In general, however, the thin ferromagnetic metal film layers have a drawback that the film layers are readily corroded, and therefore the storage stability thereof is not good. Further, when the magnetic recording media comprising thin ferromagnetic metal films are used as magnetic tapes and moved in magnetic recording and reproducing apparatus, the thin ferromagnetic metal film layers are readily scratched by contact with the magnetic head or guide posts of the apparatus.